Women cat owners are 'more likely to kill themselves' due to higher chance of infection with parasite found in feline faeces
Women infected with Toxoplasma gondii are one-and-a-half times more likely to attempt suicideThird of world's population is infected with parasite, which hides in cells in the brain and muscles, often without producing symptoms

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UPDATED:

08:52 GMT, 3 July 2012

Female cat owners are more likely to suffer mental health problems and commit suicide because they can be infected with a common parasite that can be caught from cat litter, according to a study.

Women infected with the Toxoplasma gondii – or T. gondii – parasite, which is spread through contact with cat faeces or eating undercooked meat or unwashed vegetables, are at increased risk of suicidal thoughts.

About a third of the world’s population
is infected with the parasite, which hides in cells in the brain and
muscles, often without producing symptoms.

Risk Female cat owners are more likely to commit suicide because they can be infected with a common parasite that can be caught from cat litter

Risk Female cat owners are more likely to commit suicide because they can be infected with a common parasite that can be caught from cat litter

The infection, which is called
toxoplasmosis, has been linked to mental illness, such as schizophrenia,
and changes in behaviour.

Scientists from the U.S., Denmark, Germany and Sweden looked at more than 45,000 Danish women who gave birth between 1992 and 1995.

Babies
don’t produce antibodies to T. gondii until three months after they are
born, so the antibodies present in their blood represented infection in
the mothers.

The scientists
scoured Danish health registries to determine if any of women
diagnosed as infected later attempted suicide, including cases of violent suicide attempts
which may have involved guns, sharp instruments and jumping from high
places.

They found
that women infected with T. gondii were one-and-a-half times more likely
to attempt suicide compared to those who were not infected, and the
risk seemed to rise with increasing levels of the T. gondii antibodies.

Lead researcher Dr Teodor Postolache, from the University of Maryland, said: 'We can’t say with certainty that T. gondii caused the women to try to kill themselves, but we did find a predictive association between the infection and suicide attempts later in life that warrants additional studies.'

Toxoplasma gondii thrives in the intestines of cats and is spread through oocysts passed in their faeces

The study is the largest ever to try and ascertain a link between T.
gondii and attempted suicide and the first prospective study to document
suicide attempts that occurred after the infection was discovered.

Dr Postolache’s research team at the University of Maryland was the first
to report a connection between T. gondii and suicidal behaviour in 2009.

The parasite thrives in the
intestines of cats and is spread through oocysts passed in their
faeces.

All warm-blooded animals can become infected through ingestion
of these oocysts. The organism spreads to their brain and muscles,
hiding from the immune system within 'cysts' inside cells.

Humans
can become infected by changing their infected cats’ litter boxes,
eating unwashed vegetables, drinking water from a contaminated source or, more commonly, by eating undercooked or raw meat that is infested
with cysts.

Not washing
kitchen knives after preparing raw meat before handling another food
item also can lead to infection.

Pregnant women can pass the parasite
directly to their unborn babies and are advised not to change cat litter
boxes to avoid possible infection.

Dr Postolache noted the study's limitations, such as the inability to determine the cause of suicidal behaviour.

He added: 'T. gondii infection is likely not a random event and it is conceivable that the results could be alternatively explained by people with psychiatric disturbances having a higher risk of becoming T. gondii infected prior to contact with the health system.'

The findings are published online in the Archives of General Psychiatry.